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我有一个ViewPager托管在一个片段中，该片段托管两个由SQLite 查询返回ListFragments的填充。Cursor我最近在我的操作栏中添加了一个微调器，它允许用户对ViewPager. 但是，每次选择微调器时，即使当前显示第一个列表，也只会对第二个列表进行排序。似乎ViewPager没有跟踪当前显示的ListFragment.

我尝试getItemPosition在我的适配器中覆盖并使用 n otifyDataSetChanged，但这没有帮助。我尝试缓存当前活动片段的位置onAttach()也无济于事。我还尝试使用OnSortChanged我的适配器实现的接口来尝试重新创建ListFragments. 我在这里真的很茫然。这是我当前的代码：

我的主要片段：

public class BeerMenuFragment extends SherlockFragment {

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.beer_menu_fragment, container,
            false);
    ViewPager pager = (ViewPager) view.findViewById(R.id.beer_pager);

    pager.setAdapter(buildAdapter());
    return view;
}

private PagerAdapter buildAdapter() {
    return (new BeerMenuAdapter(getChildFragmentManager()));
}
}

我的FragmentPagerAdapter：

public class BeerMenuAdapter extends FragmentPagerAdapter {
private final int NUM_ITEMS = 2; 

public BeerMenuAdapter(FragmentManager fm) {
    super(fm);
}

/*
 * (non-Javadoc)
 * 
 * @see android.support.v4.view.PagerAdapter#getPageTitle(int)
 */
@Override
public CharSequence getPageTitle(int position) {
    return BeerListFragment.getTitle(position);
}

@Override
public int getCount() {
    return NUM_ITEMS;
}

@Override
public Fragment getItem(int position) {
    return BeerListFragment.newInstance(position);
}
}

最后，ListFragment：

public class BeerListFragment extends SherlockListFragment implements
    OnNavigationListener {
private static final String KEY_POSITION = "position";
private static final String KEY_SPINNER = "ab_spinner";
private IconicAdapter adapter;
private static final String[] LABELS = { "Newest First", "Oldest First",
        "Alphabetical" };
private Context ctxt;
private int mShowItems;
private Cursor data;
private boolean synthetic = true;

static BeerListFragment newInstance(int position) {
    BeerListFragment frag = new BeerListFragment();
    Bundle args = new Bundle();

    args.putInt(KEY_POSITION, position);
    frag.setArguments(args);
    return (frag);
}

static String getTitle(int position) {
    String header = "Draft";
    switch (position) {
    case 0:
        header = "Draft";
        break;
    case 1:
        header = "Bottle";
        break;
    }
    return (header);
}

/*
 * (non-Javadoc)
 * 
 * @see
 * android.support.v4.app.ListFragment#onCreateView(android.view.LayoutInflater
 * , android.view.ViewGroup, android.os.Bundle)
 */
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
        Bundle savedInstanceState) {
    View result = inflater.inflate(R.layout.menu_list_fragment, container,
            false);

    ctxt = getActivity().getApplicationContext();
    SQLiteDatabase db = DatabaseHelper.getInstance(ctxt)
            .getReadableDatabase();

    SherlockFragmentActivity activity = getSherlockActivity();
    ArrayAdapter<String> show = null;
    ActionBar bar = activity.getSupportActionBar();

    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
        show = new ArrayAdapter<String>(bar.getThemedContext(),
                android.R.layout.simple_spinner_item, LABELS);
    } else {
        show = new ArrayAdapter<String>(activity,
                android.R.layout.simple_spinner_item, LABELS);
    }

    show.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    bar.setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);
    bar.setListNavigationCallbacks(show, this);

    if (savedInstanceState != null) {
        bar.setSelectedNavigationItem(savedInstanceState
                .getInt(KEY_SPINNER));
    }

    data = getBeerMenuDbData(db, mShowItems);

    // set up list adapter
    adapter = new IconicAdapter(ctxt, data);

    setListAdapter(adapter);
    return (result);
}

private Cursor getBeerMenuDbData(SQLiteDatabase db, int showItems) {
    String order;
    String WHERE;
    switch (showItems) {
    case 1: // Oldest First
        order = DbContract.BeerEntry.COLUMN_MODIFIED + " ASC";
        break;
    case 2: // Alphabetical
        order = DbContract.BeerEntry.COLUMN_TITLE + " ASC";
        break;
    default: // Newest first
        order = DbContract.BeerEntry.COLUMN_MODIFIED + " DESC";
        break;
    }
    String[] COLUMNS = { DbContract.BeerEntry._ID,
            DbContract.BeerEntry.COLUMN_TITLE,
            DbContract.BeerEntry.COLUMN_MODIFIED };
    WHERE = "serving='" + getTitle(getArguments().getInt(KEY_POSITION, -1))
            + "'";
    return db.query(DbContract.BeerEntry.TABLE_NAME, COLUMNS, WHERE, null,
            null, null, order);
}

class IconicAdapter extends CursorAdapter {
    LayoutInflater inflater;

    IconicAdapter(Context context, Cursor data) {
        super(context, data, 0);
        inflater = LayoutInflater.from(context);
    }

    @Override
    public void bindView(View view, Context context, Cursor cursor) {
        String dateString = cursor.getString(2);
        String[] dateArray = new String[3];
        TextView beerName = (TextView) view.findViewById(R.id.beerName);
        TextView date = (TextView) view.findViewById(R.id.drinkDate);
        RatingBar rb = (RatingBar) view.findViewById(R.id.ratingBar1);

        beerName.setText(cursor.getString(1));
        if (!dateString.isEmpty()) {
            dateArray = dateString.split("-");
            date.setText(dateArray[1] + "/" + dateArray[2] + "/"
                    + dateArray[0]);
        } else {
            date.setText(dateString);
        }
        rb.setRating((float) Math.random() * 5.0f);
    }

    @Override
    public View newView(Context context, Cursor cursor, ViewGroup parent) {
        return inflater
                .inflate(R.layout.beer_club_list_item, parent, false);
    }
}

/*
 * (non-Javadoc)
 * 
 * @see android.support.v4.app.Fragment#onDestroy()
 */
@Override
public void onDestroy() {
    super.onDestroy();
    ((CursorAdapter) getListAdapter()).getCursor().close();
}

@Override
public boolean onNavigationItemSelected(int itemPosition, long itemId) {
    if (synthetic) {
        synthetic = false;
        return true;
    }

    mShowItems = itemPosition;
    SQLiteDatabase db = DatabaseHelper.getInstance(ctxt)
            .getReadableDatabase();
    Cursor newData = getBeerMenuDbData(db, mShowItems);
    adapter.changeCursor(newData);
    return true;
}

@Override
public void onSaveInstanceState(Bundle outState) {
    outState.putInt(KEY_SPINNER, getSherlockActivity()
            .getSupportActionBar().getSelectedNavigationIndex());
}
}

提前感谢您的帮助！

4

1 回答 1

1

所以，你的问题是你bar.setListNavigationCallbacks(show, this)在你BeerListFragment的 s. 当您的 1stBeerListFragment在您的 中创建时ViewPager，它将自己设置为导航选择的回调。然后，当您的 2ndBeerListFragment创建时（ViewPagers 恢复当前可见页面的左侧和右侧的页面），它将自己设置为导航选择的回调，并覆盖1st BeerListFragment，现在将不再获得onNavigationItemSelected回调。

这一切都与您所看到的行为有关，最后一个BeerListFragment调用bar.setListNavigationCallbacks将是唯一接收onNavigationItemSelected回调的人。这就是为什么只对第二个BeerListFragment进行排序的原因。

为了解决这个问题，我建议你做一些事情：

  1. 管理在 中为导航选择设置回调，并将结果传递给处于“活动”（在 中）中BeerMenuFragment的子s 。为此，您需要使用此处的答案之一。FragmentonResume
  2. 存储最新应用的排序选项，并签入onResume每个选项BeerListFragment以查看其排序是否匹配，如果不匹配，则应用排序。

这将保证您的所有排序都应用于 中的所有页面ViewPager，无论它们在应用排序时是否显示。

于 2013-04-26T16:24:10.277 回答